Generally, a compressor is for compressing a fluid. The compressor can be divided into a rotation compressor, a reciprocating compressor and a scroll compressor, etc. according to fluid compression types. The compressor consists of a sealed container; a motor part installed inside the sealed container and generating a driving force; and a compression part receiving the driving force of the motor part and compressing gas.
In the compressor, when power is applied, the motor is operated and generates a driving force, the driving force is transmitted to the compression part, and accordingly the compression part sucks, compresses and discharges gas.
FIG. 1 is a longitudinal sectional view illustrating the compression part of the conventional compressor of the background art. As depicted in FIG. 1, the compression part of the compressor includes a frame 10 having a through hole 11; a cylinder 20 having an internal compression space 21 and combined with the through hole 11 of the frame 10; a piston 30 having a cylindrical shape, inserted into the compression space 21 and connected to the motor part; a discharge cover 40 for covering the compression space 21 of the cylinder 20; a discharge valve 50 inserted into the discharge cover 40 and opening/closing the compression space 21 of the cylinder 20 by a pressure difference; and a valve spring 51 inserted into the discharge cover 40 and supporting the discharge valve 50.
The discharge cover 40 and the cylinder 20 are combined with the frame 10 by plural bolts 60.
The frame 10 includes a body part 12 having a certain shape; a plate portion 13 extending from a certain side of the body part 12 so as to have a certain size; a through hole 11 formed at the body part 12; and a plurality of bolt or screw holes 14 formed at the plate portion 13.
The cylinder 20 includes a cylinder body 22 having an outer diameter corresponding to that of the through hole 11 of the frame 10 and a certain length; a flange portion 23 extending from the end of the cylinder body 22 so as to be at the same plane as that of the cylinder body 22 and having a certain thickness and width; a compression space 21 formed inside the cylinder body 22 so as to have a certain inner diameter; and a plurality of combining holes 24 formed at the flange portion 23.
The discharge cover 40 includes a plenum portion 41 having a cap shape to have a certain inner space; a flange portion 42 radially extending from the plenum portion 41 so as to have a certain width; a discharge hole 43 formed at a certain side of the plenum portion 41; and plural combining holes 44 formed at the flange portion 42.
A discharge pipe (not shown) for discharging gas is combined with the discharge hole 43 of the discharge cover 40.
First, the body 22 of the cylinder 20 is inserted into the through hole 11 of the frame 10, the flange portion 23 of the cylinder 20 contacts to a certain surface of the plate portion 13 of the frame 10, and accordingly the cylinder 20 is combined with the frame 10.
And, when the discharge valve 50 and the valve spring 51 are inserted into the inner space of the plenum portion 41 of the discharge cover 40, to make the discharge cover 40 cover the compression space 21 of the cylinder 20, the flange portion 42 of the discharge cover 40 is contacted to the flange portion 23 of the cylinder 20.
Herein, the discharge valve 50 placed inside the discharge cover 40 blocks the compression space 21 of the cylinder 20 by being elastically supported by the valve spring 51.
And, the combining hole 24 of the cylinder 20 and the combining hole 44 of the discharge cover 40 respectively coincide with the screw hole 14 of the frame 10, the bolt 60 is respectively fastened to the coincided screw hole 14 and the combining holes 24, 44, and accordingly the cylinder 20 and the discharge cover 40 are fixedly combined with the frame 10.
The operation of the compression part of the conventional compressor will be described.
First, when the driving force of the motor part is transmitted to the piston 30, the piston 30 performs a linear reciprocating motion in the compression space 21 of the cylinder 20.
According to the linear reciprocating motion of the piston 30, the discharge valve 50 sucks, compresses and discharges gas by opening/closing the compression space 21 of the cylinder 20.
The high temperature-high pressure gas discharged from the compression space 21 of the cylinder 20 passes the inner space of the plenum portion 41 of the discharge cover 50 and is discharged to the outside through the discharge hole 43 and the discharge pipe combined with the discharge hole 43.
However, in the compression part of the conventional compressor, in combining of the cylinder 20 and the discharge cover 40 with the frame 10, because the combining hole 24 of the cylinder 20 and the combining hole 44 of the discharge cover 40 are respectively combined with the screw hole 14 of the frame 10 by the bolts 60, the assembly process of those parts are intricate. In addition, it is difficult to coincide the center of the compression space 21 of the cylinder 20 with the inner space center of the plenum portion 41 of the discharge cover 40.
And, due to a fabrication error in surface-processing of the flange portion 42 of the discharge cover 40 and the flange portion 23 of the cylinder 20, a gap may occur between the flange portion 42 of the discharge cover 40 and the flange portion 23 of the cylinder 20, in that case, the high temperature-high pressure gas discharged from the compression space 21 of the cylinder 20 may leak through the gap between the flange portion 42 of the discharge cover 40 and the flange portion 23 of the cylinder 20.
And, while compressing and discharging the gas in the compression space 21 of the cylinder 20, because high temperature heat generated at the discharge side of the cylinder 20 can not be sufficiently cooled, construction parts may be deformed.